Last December the U.S. Army ordered the first hundred MUOS (satellite communication) upgrade kits (some additional hardware and software) for PRC-155 radios. The 6.4 kg (14 pounds, one third of that is batteries) PRC-155 radios are used in vehicles and carried by infantry. This is the latest vehicle/manpack radio design and is replacing the PRC-150, which were widely adopted in the last decade, initially by SOCOM (Special Operations Command). The army recently ordered the first 3,726 PRC-155s and will eventually buy over 50,000 of them. Most of these will have the MUOS add-on kit. The PRC-155 is equipped to provide Internet-like capabilities on the battlefield and MUOS gives access to a world-wide net. This is a big deal for ground troops because existing radios often had their range greatly reduced by terrain (hills or many tall buildings) or weather (electric disturbances high up). A satellite link eliminates this problem and ground troops have been asking for this for a long time. “PRC” means “portable radio,” and while the PRC radios have been getting lighter since World War II (when they weighed more than twice as much as the PRC-155), range and interference remained a problem.

MUOS (Mobile User Objective System) is a new military communications system. MUOS will give military users cell-phone-like capabilities anywhere in the world. Four communications satellites operating in 36,000 kilometer stationary (geosynchronous) orbits provide superior satellite phone service that is also encrypted and capable of working despite being in forests or most buildings. In effect, MUOS can replace cell phone towers in any area on the planet once the signals from one of the four satellites are aimed at the area of operations. The complete system is supposed to be active by 2016. The first satellite went up last February. The four ground stations (one for each satellite) are in Sicily, North America, Hawaii, and Australia.